Self-locking bearing ring



March 31, 1970 k. s. How, JR 3,503,121

SELF-LOCKING BEARING RING Filed Nov. '9. 196'? INVENTOR PAMMJYHOW JQUnited States Patent 3,503,121 SELF-LOCKING BEARING RING Ralph S. Howe,Jr., New Britain, Conn., assignor, by mesne assignments, to TextronInc., Providence, R.I., a corporation of Delaware Filed Nov. 9, 1967,Ser. No. 681,627 Int. Cl. B21d 53/12 U.S. Cl. 29527.2 7 Claims ABSTRACTOF THE DISCLOSURE The invention contemplates fabrication of a resilientself-locking structure in the bore of a ring to be mounted on a shaft.The structure involves an annulus of elastomeric material bonded to thebore and having a bore of diameter to encounter interference with agiven shaft diameter, on which the resiliently lined ring is to bemounted. Plural angularly spaced metal feet are embedded in theelastomeric material, the feet being in radial clearance relation withthe bearing ring bore and having inner surfaces exposed at the bore ofthe elastomeric material. Thus, the interference encountered upon shaftinsertion develops resiliently loaded radially outward displacement ofthe clamping feet.

This invention relates to a method and apparatus involving aself-locking mechanism for attachment of a ring, such as aninner-bearing ring, to a shaft, particularly for light-dutyapplications.

In certain applications, it is desired that collars, bearing rings andthe like be completely self-contained and adaptable, upon axialinsertion, to resiliently hug a shaft. It is known to make suchstructures utilizing a hub or bushing of elastomeric material, which mayor may not be bonded in the bore of the ring to be mounted. However,such devices are subject to the difliculty that they are entirely tooresiliently mounted and have insufficient bite upon the shaft to assureagainst angular creep, due to planetary action in the presence of eventhe lightest loads.

It is, accordingly, an object of the invention to provide an improvedstructure of the character indicated.

It is a specific object to meet the foregoing object with a structure inwhich metal feet may be an instrumentality for resiliently loadedself-locking contact with and mounting of a ring, such as a bearingring, upon a shaft.

Another specific object is to provide a self-locking or self-mountingbearing ring or the like with plural uni form metal feet which areresiliently positioned and which inherently position the ringconcentrically upon the shaft to which it is mounted.

Still another object is to meet the foregoing objects with a structurein which an interference fit between resilient clamping feet in aself-locking bearing ring may (1) be relied upon to develop relativelystrong resistance against planetary creep in the presence of loads, and(2) at the same time be effectively applicable to a relatively widetolerance range of shaft diameters.

Another object is to provide a method for achieving a structure meetingthe foregoing objects.

Other objects and various further features of novelty and invention willbe pointed out or will occur to those skilled in the art from a readingof the following specification in conjunction with the accompanyingdrawings. In said drawings, which show for illustrative purposes only,preferred forms and methods of the invention:

FIG. 1 is a view in end elevation of a ball bearing to which resilientmounting structure of the invention has een applied;

FIG. 2 is a similar end elevation view of the inner bearing ring of FIG.1 in an early formative step, i.e., prior to completion of the method ofthe invention;

FIG. 3 is an enlarged fragmentary view in section, taken in the plane 33of FIG. 2 and partly broken away to reveal the section at the radialplane 3' of FIG. 2;

FIG. 4 is a view in perspective of a clamping-ring structure utilized inthe method of the invention and prior to its embodiment and treatmentaccording to that method;

FIG. 5 is a view similar to FIG. 2 but illustrating the structure afterperformance of method steps of the invention;

FIG. 6 is an enlarged fragmentary sectional view similar to FIG. 3 butillustrative of the performance of the method step illustrated in FIG.5, the section of FIG. 6 being taken in the plane 66 of FIG. 5, and partof that section being broken away to reveal the section at the radialplane 6 in FIG. 5;

FIG. 7 is an enlarged fragmentary end view in elevation of the structureof FIG. 5, before application to a shaft;

FIG. 8 is a view similar to FIG. 7 showing radial displacementsoccasioned by interference when fitting the shaft to the structure ofFIGS. 5 and 7; and

FIGS. 9 and 10 are similar end-elevational views illustrating amodification, FIG. 9 being taken prior to completion of the method, andFIG. 10 representing the finished structure after performing the methodof the invention.

Briefly stated, the invention contemplates fabrication of a resilientself-locking structure in the bore of a ring to be mounted on a shaft.The structure involves an ananulus of elastomeric material bonded to thebore and having a bore of diameter to encounter interference with agiven a shaft diameter, on which the resiliently lined ring is to bemounted. Plural angularly spaced metal feet are embedded in theelastomeric material, the feet being in radial clearance relation withthe bearing ring bore and having inner surfaces exposed at the bore ofthe elastomeric material. Thus, the interference encountered upon shaftinsertion develops resiliently loaded radially outward displacement ofthe clamping feet.

According to the method of making such structure, the clamp feet aredefined by a single rigid clamp ring of initial inner dimensions whichinterfere with the shaft diameter. This single clamp ring has outerdimensions to fit with radial clearance within the bore of the ringbody, and plural angularly spaced grooves of depth extending to lessthan the diameter of the shaft. The ring is concentrically embeddedwithin and bonded by elastomeric material within the bore of the bearingring body. A subsequent boring operation on the resulting compositestructure is performed to a diameter suflic-ient to sever the clampedring at the groove bottom locations, thereby defining plural resilientlyvmounted clamp feet within the ring body.

Referring to FIG. 1 of the drawings, the invention is shown inapplication to an antifriction bearing having the usual inner and outerrace rings 10-11 with plural spaced antifriction elements, such as balls12 riding raceways in the radially facing surfaces of the rings 10-11.The invention provides a self-locking or clamping structure within thebore of the inner bearing ring 10. It suffices in connection with FIG. 1to state that this clamping structure involves, for the form shown,three equally angularly spaced metal clamping feet 13-1445 of relativelysubstantial arcuate extent and concentrically positioned, at relativelyclose angular spacing, within the bore of the inner ring 10, the samebeing embedded in elastomeric material 16.

FIGS. 2 to 8 illustrate the method used in the fabrication of theself-locking structure of FIG. 1. Such method involves selection of arigid unitary clamp-ring structure as illustrated in FIG. 4. Thisstructure is shown as a cylindrical annulus, as of steel, having acontinuous cylindrical bore 17 between its axial ends, and having anouter cylindrical surface which is interrupted by angularly spacedrelatively narrow channels or grooves 18-19, thus defining relativelyangularly extensive body elements, as at 20, between grooves 18-19. Thebody element 20 eventually becomes one of the jaws or feet in theclamping structure; the other two jaw or foot elements are identified at21-22 in FIG. 4. For the form shown, the end faces of the clamping ringof FIG. 4 are provided with bevels or chamfers, as at 23 at the bore 17and extending to an outer diameter or limit 24 which exceeds the shaftdiameter on which the ring is to be mounted. Further, the depth of thegrooves 18-19 is to an extent representing a diameter less than theshaft diameter on which the selflocking device is to be mounted.

The ring of FIG. 4 is concentrically positioned within the inner bearingring 10' and this fact or condition is illustrated in FIG. 2. The tworing structures in such concentric relation are then placed in a mold,so that elastomeric material 25 may fill all voids between the clampringbore and the inner bearing-ring bore. The resultant structure is bestillustrated in FIG. 3 wherein it will be seen that the bottoms of thegrooves (18) define, with the bore of the clamping ring of FIG. 4, thinconnecting elements or bridges, identified at 26 in FIG. 3. These connecting elements are ultimately removed by a boring, turning or grindingoperation to enlarge the bore of the composite structure to a diameterjust less than the ultimate shaft diameter. The extent of theinterference with the shaft diameter is predetermined, based on thedesired resiliently loaded displacement of feet 20-21-22, thickness andstiffness of the elastomeric material, radial loading of the bearing,and other factors, as will be understood.

After performing the boring, turning or grinding operation, thecomposite structure has the appearance displayed in FIG. 5 wherein bodyelements 20-21-22 have been severed because the bridge material 26 whichpreviously connected them has now been removed. The bore is concentricwith the inner bearing ring, and all feet or body elements 20-21-22 haveprecisely the same radius, being a radius slightly less than that of theshaft on which the self-clamping structure is to be mounted. Moreover,all body elements or feet 20-21-22 are uniformly resiliently supportedby precisely the same radial thickness of the elastomeric materialwithin the bore of the inner bearing ring 10. The enlarged view of FIG.6 displays the condition of the locking structure after performing thesemethod steps.

FIGS. 7 and 8 illustrate displacements which occur upon mounting theinner bearing ring 10 and its selfclamping structure on a shaft 30 ofdiameter which in FIG. 8 is shown to have exaggerated interference fitwith the bore of the composite self-locking structure. It will be seenthat this interference fit necessarily involves uniform radially outwarddisplacement of each of the clamping feet 20-21-22 by reason ofcomplaint yielding of the body of elastomeric material 25, and that byreason of the smaller finish radius on each of the clamping feet 20-21-22 as compared with the shaft radius, there necessarily results foreach of these feet two spaced essentiallyline contacts 31-32 with theshaft surface. The nature of resilient loading of each foot (20) on theshaft is to develop strong biting action at 31-32 to resist creep, tostabilize radial orientation of the ultimate bearing, and better tosustain stable quiet running of whatever mechanism is mounted by thebearing.

It will be observed furthermore that by having formed the chamfers orbevels at 23 for each axial end of the bore 17, the potting ofelastomeric material necessarily fills the annular void inside thechamfer or bevel 43. This is illustrated in enlarged detail at 23' inFIG. 3. This filling survives as a circumferentially continuous seal .4structure even after performing the boring, turning or grinding step ofthe method, i.e., even after the bridge connections 26 betweenclamp-feet 20-21-22 have been severed. By providing such acircumferentially continuous edge, there is assurance against the entryof foreign matter into the clamping structure, and there is assurancethat the clearance developed between the shaft and the center of eachclamping foot, as at 34 (FIG. 8), will be protected against entry offoreign matter and moisture, so that prime reliance at all times can behad upon the grip at 31-32 to sustain and hold the ring mounting uponthe shaft.

FIGS. 9 and 10 illustrate a modification wherein the rigid clamp ringwhich ultimately defines the spaced clamping feet or jaws is itself ofcorrugated construction, such as corrugated steel with longitudinalflutings. The corrugated clamp ring of FIG. 9 is identified 35 and isseen to provide plural angularly spaced outwardly facing grooves 36; thedepth of such grooves is preferably to a diameter less than the ultimateshaft diameter to which the composite structure is to be mounted, andthe corrugated ring 35 is potted or embedded in elastomeric material 37in the manner previously described. Once potted, the composite structureis subjected to boring, turning or grinding operations to severindividual undulations of the ring 35 at the groove bottoms, as atlocation 38 in FIG. 9. The resultant structure is illustrated in FIG. 9after performing the boring or grinding operation. This finishingoperation enlarges the bore 39 to a diameter just less than the ultimateshaft diameter upon which the composite structure is to be mounted, andis seen to provide plural severed feet 40-41, as inverted U-shapedstructures. The arm extremities of each U face radially inwardly and arefinished with a radius (about the axis of the composite structure) oflesser extent than the ultimate shaft diameter to which the device is tobe mounted. This assures that for mounting to such a shaft, all feet40-41 will be uniformly radially outwardly displaced, and two angularlyspaced lines of contact will be developed for each resilienty loadedfoot 40-41, in the manner described for the feet 20-21-22 in thearrangement of FIGS. 1 to 8.

It will be seen that I have described a basically simple and improvedself-locking structure and method, particularly applicable to any ringstructure to be mounted upon a shaft, and having special application forthe case of antifriction bearings. This structure provides inherentsymmetry of support and enhanced grip on a shaft, through uniformlyapplied resilient loading that is completely concentric. The support andgrip are effective over relative larger a tolerance range for shaftdiameter, and quiet running is promoted. Moreover, the nature of thegrip is such as to provide inherently less tendency to develop lessfretting corrosion between a shaft and hearing bore, as compared withconventional slip-fitted locking devices applied to bearings.

Although the invention has been described in connection with preferredforms and methods, it will be understood that modifications may be madewithout departing from the scope of the invention as defined in theclaims which follow.

What is claimed is:

1. The method of making a self-locking ring for attachment to a shaft,which comprises selecting a rigid ring body of bore diameter to clearthe shaft diameter, selecting a rigid clamp ring of inner dimensionswhich interfere with the shaft diameter and outer dimensions to fit withradial clearance within the bore of said ring body, said clamp ringhaving plural angularly spaced grooves of depth extending to less thanthe diameter of the shaft, embedding said clamp ring in elastomericmaterial and in the bore of said ring body, and then boring theresulting composite structure to a diameter sufficient to sever saidclamp ring at groove-bottom locations, and to expose at said bore alimited arc of the elastomeric material between severed parts of saidclamp ring, thereby defining plural resiliently mounted arcuate clampfeet within said ring body.

2. The method according to claim 1, in which said clamp ring is acylindrical annulus longitudinally channelled on its outer surface todefine the grooves, whereby the clamp feet are characterized byrelatively extensive arcuate surfaces.

3. The method according to claim 1, wherein said lastdefined boring stepis to a diameter less than the shaft diameter, whereby initialinterference to shaft insertion is resiliently backed and, upon shaftinsertion, each foot develops two resiliently loaded line contacts withthe shaft.

4. The method according to claim 1, wherein the axial ends of said clampring are chamfered at the bore thereof, the chamfer extending to anouter diameter beyond that to which the last-defined boring operation isperformed, whereby at each axial limit of the composite ring structure,a circumferentially continuous elastomeric shafthugging seal is defined.

5. The method of claim 1, in which the clamp ring is a corrugated metalannulus wherein the grooves are defined by the outwardly facingperipheral undulations thereof.

6. The method of making a molded annular ring with like angular spacedmetal segments on the inner surface thereof at a predetermined borediameter, which comprises selecting a metal ring of inner dimension lessthan said predetermined bore diameter of said inner surface, said ringhaving plural angularly spaced grooves of depth extending to less thansaid predetermined diameter,

molding said ring at the bore of a ring of elastomeric material, andthen boring the resulting composite structure to a diameter sufiicientto sever said ring at groovebottom locations, and to expose at said borea limited arc of the elastomeric material between severed parts of saidclamp ring, thereby defining plural resiliently mounted and angularlyspaced arcuate metal segments within the annular ring.

7. The method of claim 1, wherein said first-mentioned ring body is aninner ring having a circumferentially extending bearing raceway on theouter surface thereof and about a central axis, and wherein said rigidclamp ring is positioned concentrically within the bore of saidfirstmentioned ring body during the embedding step, and further whereinthe boring step is performed concentrically with said axis.

References Cited UNITED STATES PATENTS 629,395 7/1899 Sargent 29-1495 X1,643,977 10/1927 Buckwalter .29148.4 X 2,982,999 5/1961 Stewart29--148.4 X 3,061,386 10/1962 Dix et al. 29148.4 X 3,335,481 8/1967Haentjens 29-529 X 3,348,289 10/1967 Marsh .29-149 3,382,567 5/1968Schaeffier 29149 WAYNE A. MORSE, JR., Primary Examiner US. Cl. X.R.

